mgcp: Prepare the CRCX/MDCX/DLCX messages for the transcoder.
Send CRCX/MDCX/DLCX to the transcoder, fill out transcoder_end with
the interesting data and hope that it is going to work.
diff --git a/openbsc/src/mgcp/mgcp_protocol.c b/openbsc/src/mgcp/mgcp_protocol.c
index 8010006..6d9a6b4 100644
--- a/openbsc/src/mgcp/mgcp_protocol.c
+++ b/openbsc/src/mgcp/mgcp_protocol.c
@@ -89,6 +89,9 @@
static struct msgb *handle_modify_con(struct mgcp_config *cfg, struct msgb *msg);
static struct msgb *handle_rsip(struct mgcp_config *cfg, struct msgb *msg);
+static void create_transcoder(struct mgcp_endpoint *endp);
+static void delete_transcoder(struct mgcp_endpoint *endp);
+
static uint32_t generate_call_id(struct mgcp_config *cfg)
{
int i;
@@ -512,6 +515,7 @@
break;
case MGCP_POLICY_DEFER:
/* stop processing */
+ create_transcoder(endp);
return NULL;
break;
case MGCP_POLICY_CONT:
@@ -526,6 +530,7 @@
if (cfg->change_cb)
cfg->change_cb(cfg, ENDPOINT_NUMBER(endp), MGCP_ENDP_CRCX);
+ create_transcoder(endp);
return create_response_with_sdp(endp, "CRCX", trans_id);
error:
LOGP(DMGCP, LOGL_ERROR, "Malformed line: %s on 0x%x with: line_start: %d %d\n",
@@ -719,6 +724,7 @@
break;
case MGCP_POLICY_DEFER:
/* stop processing */
+ delete_transcoder(endp);
return NULL;
break;
case MGCP_POLICY_CONT:
@@ -730,6 +736,8 @@
/* free the connection */
LOGP(DMGCP, LOGL_DEBUG, "Deleted endpoint on: 0x%x Server: %s:%u\n",
ENDPOINT_NUMBER(endp), inet_ntoa(endp->net_end.addr), ntohs(endp->net_end.rtp_port));
+
+ delete_transcoder(endp);
mgcp_free_endp(endp);
if (cfg->change_cb)
cfg->change_cb(cfg, ENDPOINT_NUMBER(endp), MGCP_ENDP_DLCX);
@@ -848,3 +856,97 @@
memset(&endp->taps, 0, sizeof(endp->taps));
}
+
+/* For transcoding we need to manage an in and an output that are connected */
+static int back_channel(int endpoint)
+{
+ return endpoint + 60;
+}
+
+static void send_msg(struct mgcp_endpoint *endp, int endpoint, int port,
+ const char *msg, const char *mode)
+{
+ struct sockaddr_in addr;
+ char buf[2096];
+ int len;
+
+ /* hardcoded to AMR right now, we do not know the real type at this point */
+ len = snprintf(buf, sizeof(buf),
+ "%s 42 %x@mgw MGCP 1.0\r\n"
+ "C: 4256\r\n"
+ "M: %s\r\n"
+ "\r\n"
+ "c=IN IP4 %s\r\n"
+ "m=audio %d RTP/AVP %d\r\n"
+ "a=rtpmap:%d %s\r\n",
+ msg, endpoint, mode, endp->cfg->source_addr,
+ port, endp->cfg->audio_payload,
+ endp->cfg->audio_payload, endp->cfg->audio_name);
+
+ if (len < 0)
+ return;
+
+ buf[sizeof(buf) - 1] = '\0';
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sin_family = AF_INET;
+ addr.sin_addr = endp->cfg->transcoder_in;
+ addr.sin_port = htons(2427);
+ sendto(endp->cfg->gw_fd.bfd.fd, buf, len, 0,
+ (struct sockaddr *) &addr, sizeof(addr));
+}
+
+static void send_dlcx(struct mgcp_endpoint *endp, int endpoint)
+{
+ struct sockaddr_in addr;
+ char buf[2096];
+ int len;
+
+ len = snprintf(buf, sizeof(buf),
+ "DLCX 43 %x@mgw MGCP 1.0\r\n"
+ "C: 4256\r\n"
+ , endpoint);
+
+ if (len < 0)
+ return;
+
+ buf[sizeof(buf) - 1] = '\0';
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sin_family = AF_INET;
+ addr.sin_addr = endp->cfg->transcoder_in;
+ addr.sin_port = htons(2427);
+ sendto(endp->cfg->gw_fd.bfd.fd, buf, len, 0,
+ (struct sockaddr *) &addr, sizeof(addr));
+}
+
+static void create_transcoder(struct mgcp_endpoint *endp)
+{
+ int port;
+ int in_endp = ENDPOINT_NUMBER(endp);
+ int out_endp = back_channel(in_endp);
+
+ if (!endp->cfg->transcoder_ip)
+ return;
+
+ send_msg(endp, in_endp, endp->bts_end.local_port, "CRCX", "recvonly");
+ send_msg(endp, in_endp, endp->bts_end.local_port, "MDCX", "recvonly");
+ send_msg(endp, out_endp, endp->transcoder_end.local_port, "CRCX", "sendrecv");
+ send_msg(endp, out_endp, endp->transcoder_end.local_port, "MDCX", "sendrecv");
+
+ port = rtp_calculate_port(out_endp, 4000);
+ endp->transcoder_end.rtp_port = htons(port);
+ endp->transcoder_end.rtcp_port = htons(port + 1);
+}
+
+static void delete_transcoder(struct mgcp_endpoint *endp)
+{
+ int in_endp = ENDPOINT_NUMBER(endp);
+ int out_endp = back_channel(in_endp);
+
+ if (!endp->cfg->transcoder_ip)
+ return;
+
+ send_dlcx(endp, in_endp);
+ send_dlcx(endp, out_endp);
+}